Fluid pressure control mechanism



June 7, 1938. L. A. MAJNERI FLUID PRESSURE CONTROL MECHANISM Filed Jan. 8; 1936 0 m I 0 0 1 0. I w m INVENTOR LUD me. A. MAJNERL' Y ,5

ATTORNEY Patented June 7, 1938 UNITED STATES PATENT orrica This invention relates to a fluid pressure control mechanism and is specifically illustrated as embodied in a control mechanism for hydraulic brakes particularly applicable to airplanes.

5 An object of the invention is to provide a reciprocatingpiston in a cylinder which forms a common end Wall for a reserve chamber at one side of thepiston and a pressure chamber at the other side of the piston, and to provide a bypass in from the reserve chamber to the pressurechamher which serves a two-fold purpose. One of these purposes is to provide a communication from the reserve chamber to the pressure cham her so that the latter chamber is at all times filled 15 with fluid, and the other of said purposes is to provide a one-way passage for the fluid from the reserve chamber to the pressure chamber -serving as a means for bleeding the hydraulic braking system so that all air which might be in the fluid is removed from the pressure chamber. Other objects and advantages of the invention will more fully appear from the following description taken in connection with the accompanying drawing, in which:

Fig. l is a side elevation of my improved device mounted for operation.

Fig. 2 is a vertical sectional view of the mechanism shown in Fig. 1, taken on the line 22 thereof, and showing the parts of. the bypass in position for bleeding the system.

' Fig. 3 is a fragmentary sectional view corresponding to the upper portion of Fig. 2, the parts being-shown in normal operative position.

Fig. 4 is a fragmentary sectional view of the piston shown in Fig. 2 in a position occupied by movement of the piston rod in a direction opposite to that shown by arrow C in Fig. 2.

Referring to the drawing, I have shown a The piston 26 forms a common end wall for a reserve chamber 28 at the upper end of the cylinder and a pressure chamber 36 at the lower end thereof. The rod 24 at its upper end has a radially extending flange 32 upon which seats a screw threaded cap member 34 resiliently held against the seat by a spring 36 held on the 55 end of therod 24 by a pin and Washer 38 and 46 respectively. The head of the piston is slidably mounted on the rod 24 below the radially extending flange 32 and the skirt portion thereof is screw threaded to receive the cap member 34. It will be noted that the head of the cap' 34 and 5- 'the head of the piston 26 are spaced on the opposite sides of the radially extending flange 32,

. the latter forming a stop for relatively axial movement between the rod and piston. The spring 36 normally holds the piston in a down- 10 ward position relative to the rod 24, providing a space between the radially extending flange 32 and the head of. the piston.

A radially extending opening 42 is provided in the rod 24 just below the radially extending l5 flange 32 so that when the piston is in the position shown in Fig. 2 fluid in the space between the head of the cap 34 and the head of the piston 26 may'enter through the opening 42 into an axially extending passage 44 in the rod 24, the. passage 44 being closed by a plug 46 at its upper end. The lower end of the passage 44 communicates with aradially exten 'd ing passage 46 through the rod 24 conducting the fluid into the working chamber at the opposite side of the piston 26. Openings 50 are provided in the head of the cap 34 to conduct fluid from the reserve chamber 28 into the space between the head of the cap 34 and the head of thev piston 26. Suitable fluid sealing gaskets 52 and 54 are provided, the gasket 52 forming a seal for the piston 26 and the gasket .54 forming a seal for the rod'24 extending through Ill and the collar 66 is a reciprocating member 10 urged upwardly by a coil spring 12. The member 16 is in the form of a cylinder having a head portion I4 at its upper end and a screw threaded opening at its lower end. A head 16 is threaded into the opening at the lower end and serves as an attaching means for an. operating lever 18. On opposite sides of the member 161 have pro vided a pair of swinging arms pivotally secured to the head 14 by bolts 82 which, in normal position, as shown in Fig. 1,- serve as a rigid connection between the head 14 and the collar 66.

In the operation of the mechanism just de- 66 scribed, a pressure on the lever I8 in the direction 01 the arrow A causes a downward movementof the head I6, which movement is transmitted through arms 80 to the collar 68 which in turn applies a downward pressure to the piston rod 24, causing the collar 32 to engage the head of the piston 26 closing the opening 42, and further movement of the rod 24 pulls the piston downwardly, applying pressure to the fluid in the chamber 30. If it is desired to retain this pres-- sure after releasing the pressure on the lever I8, the arms 80 are swung in a direction indicated by the arrow B by an actuating member 84, whereupon one of a plurality of notches 86 is positioned against a shoulder 88 serving as a means to space the head 14 from the lower. end of the cylinder I0, holding the spring 12 in compressed position. It will be understood that the spring I2 in compressed position retains the fluid in the chamber 30 under pressure.

. As a source of supply for the reserve chamber 23, I have illustrated a container 90 having a conduit 92 provided with a valve 94 communicating with the chamber 28 by a suitable fitting 96 screw threaded into the' plug I2.

Formed at a side of the casing I is an enlarged portion 88 having a vertically extending passage I00 at the lower end of which is a radially extending passage I02 communicating with the pressure chamber 30, and approximately in axial alignment with the radially extending passage I02 I have provided a'pressure outlet passage I04.

4 which may be connectedto the brake operating shoulder 0. In the latter enlarged portion and mechanism, not shown. At the upper end of the passage I00 I have providedan enlarged portion which is screw threaded as at I06 to receive a fitting I08. The upper and outer end of the passage I 00 is further enlarged providing 9.

a chamber I20 for receiving a tubular member I22 having a slot I24 at its upper end. The member I22 is screw threaded into the walls of the chamber I20 and terminates below the upper end of the chamber I20, forming a space for a flat disc valve I26.

As illustrated in Fig.2, it m be noted that there is a passage from the reserve chamber 28 through opening II2, passages H6, H8 to chamber I20, through slots I24, through the fltting'I22 into the passage I00, and through passage I02 into the pressure chamber 30. The valve I26, however,'being loosely mounted in the chamber I20, prevents the flow of fluid in the opposite direction by its engagement with the upper end of the walls of the chamber I20, sealing oi the passage H8. This mechanism is shown in a position for bleeding the system. When. the piston 26 is moved in aidirection indicated by the arrow C, excess fluid is drawn from the reserve chamber 28 to the.pressure chamber 30 butthe chamber 30 is substantially filled by the fluid return from the system through passage I04, and

Thus, the device operates in the form of a pump. When movement in direction of arrow C occurs the openings 42 are uncovered and any air in chamber 30 is permitted to escape into the reserve chamber 28, while during movement in the opposite direction the openings" are closed by flange 32 contacting the piston 26. It will be understood that the container 80 is applied only during the bleeding operation.

from the chamber 28 through openings II2, II 8,

I24 and I00 into the passage I04 to the hydraulic system. The piston 26 is then moved upwardly forcing the fluid in the reserve chamber 28 through the aforesaid passages into the system, it being understood that the system is open so that fluid is drained therethrough carrying with it any air which might be in the lubricant, it not returning to either of the chamber 28 or 30. The piston 26 is then moved downwardly forcing the lubricant in the pressure chamber 30 through opening I02 to passage I04 and at the same time lubricant is supplied to the reserve chamber 28.

from the container 90. This operation is repeated until the entire system is filled with lubricant. It will be understood that when the piston 26 moves downwardly the valve I 26 closes so that the piston does not draw lubricant from the system through passages I04, I00, H8 and H2. I

When the upper'portion II4 of the fitting I08 is screwed down on the shoulder IIO, as shown in Fig. 3, the fluid from the reserve chamber 28 is shut oii so that it cannot pass through the openings H8 and H6. An annular groove I28 is provided in the portion II4 of the fitting I08 to form for testing the high level of the fluid -in the reserve chamber 28. Another opening I84-is provided in the ,wall of the cylinder I0 which is closed by a removable plug I 86, providing a means for indicating the low level of the fluid in the reserve chamber 28. I

Various changes, including the size, shape and arrangement, of parts, may be made without departing from the spirit of my invention, and it is not my intention to limit the scope thereof other than by the terms of the appended claims.

What I claim is: 1. In a fluid pressure control mechanism, the combination of a pressure chamber having a pressure discharge passage and a reserve chamber having a fluid supply passage, a bypass forming a communication between said chambers, an internally threaded chamber in said bypass, an open endchamber in axial alignment with said threaded chamber, a shoulder between said threaded into said threaded chamber through said open end chamber and having an enlarged closed outer portion beyond said radially extending passage for engagement with said shoulder, .and a one-way valve in the axially extending passage of said fitting. Y

I 2. In a fluid pressure control mechanism, the combinationfof a pressure chamber and a reserve chamber in vertical alignment, a reciprocating piston forming a common end wall between said chambers, a bypass having a, vertically extending passage and horizontally arranged end passages communicating respectively with said chambers, said vertically extending passage extending beyond the horizontal passage leading to said reserve chamber and open at its upper end, said vertically extending passage being reduced in 10 diameter to form a shoulder below the horizontal 3 passage and being screw threaded, a fitting having an outer portion fitting the outer open end of said vertically extending passage and a portion of 

